1,347 research outputs found
Using Experimental Economics to Measure the Role of Parental Generosity and Food Control in Childhood Obesity
This research uses experimental economics to measure the effect of parental generosity and child response on childhood overweight and obesity. The 'Carrot-Stick' experiment, an adaptation of the standard dictator game in which the respondent (the child) can punish or reward the dictator (the parent) based on the dictator's generosity, served as basis of our examination. Two treatments are conducted, in which the child spends his or her earnings on non-food and food items. Our empirical analysis shows significant relationships between parental weight and their level of generosity regarding food items. We conclude that child response behavior, obesigenic factors in the household, and the child's tendency toward being overweight and obese are significantly related.Overweight, Obesity, Childhood, Family, Bargaining, Carrot-Stick, Dictator, Experimental Economics, Food Consumption/Nutrition/Food Safety, Health Economics and Policy,
Photosynthetic performance of Xanthoria mawsonii C. W. Dodge in coastal habitats, Ross Sea region, continental Antarctica
Xanthoria mawsonii C. W. Dodge was found to perform well physiologically in a variety of habitats at high latitudes in continental Antarctica. The net photosynthetic rate of 7•5 μ mol CO2 kg−1 s−1 is exceptionally high for Antarctic lichens. Field and laboratory measurements proved the photosynthetic apparatus to be highly adapted to strong irradiance. The cold resistance of the photosystem II reaction centres is higher than the photosynthetic CO2 fixation process. Optimum temperature for net photosynthesis was c. 10°C. The lichen grows along water channels where it is frequently inundated and hydrated to maximum water content, although net photosynthesis is strongly depressed by super saturation. In these habitats the lichen is photosynthetically active for long periods of time. Xanthoria mawsonii also grows at sites where it depends entirely on the early spring snow melt and occasional snow fall for moisture. It has an exceptionally short reactivation phase and is able to utilize snow immediately. Recovery of activity by absorbing water vapour from air, though practically possible, seems to be of ecological importance only under snow at subzero temperatures
Photosynthetic responses of three common mosses from continental Antarctica
Predicting the effects of climate change on Antarctic terrestrial vegetation requires a better knowledge of the ecophysiology of common moss species. In this paper we provide a comprehensive matrix for photosynthesis and major environmental parameters for three dominant Antarctic moss species (Bryum subrotundifolium, B. pseudotriquetrum and Ceratodon purpureus). Using locations in southern Victoria Land, (Granite Harbour, 77°S) and northern Victoria Land (Cape Hallett, 72°S) we determined the responses of net photosynthesis and dark respiration to thallus water content, thallus temperature, photosynthetic photon flux densities and CO2 concentration over several summer seasons. The studies also included microclimate recordings at all sites where the research was carried out in field laboratories. Plant temperature was influenced predominantly by the water regime at the site with dry mosses being warmer. Optimal temperatures for net photosynthesis were 13.7°C, 12.0°C and 6.6°C for B. subrotundifolium, B. pseudotriquetrum and C. purpureus, respectively and fall within the known range for Antarctic mosses. Maximal net photosynthesis at 10°C ranked as B. subrotundifolium > B. pseudotriquetrum > C. purpureus. Net photosynthesis was strongly depressed at subzero temperatures but was substantial at 0°C. Net photosynthesis of the mosses was not saturated by light at optimal water content and thallus temperature. Response of net photosynthesis to increase in water content was as expected for mosses although B. subrotundifolium showed a large depression (60%) at the highest hydrations. Net photosynthesis of both B. subrotundifolium and B. pseudotriquetrum showed a large response to increase in CO2 concentration and this rose with increase in temperature; saturation was not reached for B. pseudotriquetrum at 20°C. There was a high level of variability for species at the same sites in different years and between different locations. This was substantial enough to make prediction of the effects of climate change very difficult at the moment
A Re-Examination of Multistage Economies in Hog Farming
Current trends in the structure of hog production in the U.S. are toward facilities that are not only larger, but also more likely to be specialized, carrying out only some of the vertically linked phases of production in the same facility. This paper investigates the cost efficiency incentives for these changes by estimating a multistage cost function for hog production. Data are from the Hog Production Practices and Costs portion of the USDA’s 2004 Agricultural Resource Management Survey
A Re-Examination of Multistage Economies in Hog Farming
Current trends in the structure of hog production in the U.S. are toward facilities that are not only larger, but also more likely to be specialized, carrying out only some of the vertically linked phases of production in the same facility. This paper investigates the cost efficiency incentives for these changes by estimating a multistage cost function for hog production. Data are from the Hog Production Practices and Costs portion of the USDA’s 2004 Agricultural Resource Management Survey
Assessment of the costs, risks and benefits of selected integrated policy options to adapt to flood and drought in the water and agricultural sectors of the Warta River Basin
- …